1. Field of the Invention
The present invention relates to a method for driving a display device. The present invention relates to a method for driving a display device including a plurality of pixels each of which has a transistor whose semiconductor layer includes an oxide semiconductor.
2. Description of the Related Art
A display device including a transistor using amorphous silicon as a driving element for display elements such as liquid crystal is widely used in commercial products such as a monitor of a computer and a television set. A manufacturing technique of a transistor using amorphous silicon has been already established and a liquid crystal panel with more than 60 inches has been produced.
Since operation speed of a transistor using amorphous silicon is slow and any further high performance cannot be expected, a thin film transistor using polysilicon has been developed. However, a crystallization step is required for forming polysilicon, which leads to cause variation in transistor characteristics and inhibits enlargement of a panel area.
In contrast, an oxide semiconductor material has been attracting attention as a transistor material besides a silicon-based material. As a material of the oxide semiconductor, a material including zinc oxide as its component is known. For example, Patent Document 1 discloses the configuration which employs a transistor including an amorphous oxide (oxide semiconductor) having an electron carrier concentration of lower than 1018/cm3 as a driving element of a display device.